The World Wide Web (The Web) is a popular computer networking platform today with millions of people daily using it for a wide variety of applications from personal e-mail and research “web surfing” to highly sophisticated business and scientific uses. The web was developed to make use of the Internet simple and easy to use. The concept was to provide Browser programs at user (client) personal computers (PCs) to interpret information from host servers using HyperText Markup Language (HTML) and graphic files. The Internet provided the communication means to interconnect web clients and servers.
Web services are programs that are accessible by a server and perform a function for the client community. A web service, in one example, provides stock ticker information. A client, knowing that a web service is available, can access the web service to accomplish an operation for which the client would otherwise have to create a program. With the availability of the web service, the client merely needs to know how to interface with the web service and he can incorporate the function of the web service into his local application.
In order for the programmer to know how to interface with the web service, he needs to understand an interfacing language. One such language is Web Service Description Language (WSDL) (according to the W3C standards found on the web at www.w3.org/TR/wsdl) which is an extensible Markup Language (XML) based language for describing the interface to a web service. A web service, operating as a content provider for a server, provides a WSDL document to client programs. The WSDL document defines interface schema such that the client knows the required format, protocol and the like for the web service interface. The client needs to understand the functionality of the web service (that it provides stock quotes and that data is encrypted for instance). Each web service defines its own terminology as well.
Web service interfacing language makes it much easier for a programmer to write code to incorporate the functionality of a web service into a custom program, however, programming knowledge (WSDL, XML, HTML etc.) is required to do this.